This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Understanding the mechanism of kinesin, the smallest known processive motor protein, is a fundamental problem in biophysics. Single molecule experiments suggest that the structural changes responsible for kinesin's dynamic motility occur within tens of microseconds. Consequently, atomic MD simulations of comparable length, which can be performed on Anton, are proposed to obtain an unbiased description of the atomic mechanism. Further, for direct comparison with experiment, we will determine the response to a fluctuating external load during the force-generating substep. The results will have general implications for understanding the mechanical interactions of many translocating motor proteins.